Early and middle Miocene ice sheet dynamics in the Ross Sea: Results from integrated core-log-seismic interpretation

Oscillations in ice sheet extent during early and middle Miocene are intermittently preserved in the sedimentary record from the Antarctic continental shelf, with widespread erosion occurring during major ice sheet advances, and open marine deposition during times of ice sheet retreat. Data from seismic reflection surveys and drill sites from Deep Sea Drilling Project Leg 28 and International Ocean Discovery Program Expedition 374, located across the present-day middle continental shelf of the central Ross Sea (Antarctica), indicate the presence of expanded early to middle Miocene sedimentary sections. These include the Miocene climate optimum (MCO ca. 17−14.6 Ma) and the middle Miocene climate transition (MMCT ca. 14.6−13.9 Ma). Here, we correlate drill core records, wireline logs and reflection seismic data to elucidate the depositional architecture of the continental shelf and reconstruct the evolution and variability of dynamic ice sheets in the Ross Sea during the Miocene. Drill-site data are used to constrain seismic isopach maps that document the evolution of different ice sheets and ice caps which influenced sedimentary processes in the Ross Sea through the early to middle Miocene. In the early Miocene, periods of localized advance of the ice margin are revealed by the formation of thick sediment wedges prograding into the basins. At this time, morainal bank complexes are distinguished along the basin margins suggesting sediment supply derived from marine-terminating glaciers. During the MCO, biosiliceous-bearing sediments are regionally mapped within the depocenters of the major sedimentary basin across the Ross Sea, indicative of widespread open marine deposition with reduced glacimarine influence. At the MMCT, a distinct erosive surface is interpreted as representing large-scale marine-based ice sheet advance over most of the Ross Sea paleo-continental shelf. The regional mapping of the seismic stratigraphic architecture and its correlation to drilling data indicate a regional transition through the Miocene from growth of ice caps and inland ice sheets with marine-terminating margins, to widespread marine-based ice sheets extending across the outer continental shelf in the Ross Sea.

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West Antarctic Ice Sheet grounding events on the Ross Sea outer continental shelf during the middle Miocene

Palaeogeography Palaeoclimatology Palaeoecology ◽

10.1016/s0031-0182(03)00400-0 ◽

2003 ◽

Vol 198 (1-2) ◽

pp. 169-186 ◽

Cited By ~ 27

Author(s):

Juan M Chow ◽

Philip J Bart

Keyword(s):

Continental Shelf ◽

Middle Miocene ◽

Ross Sea ◽

Ice Sheet ◽

Outer Continental Shelf ◽

Antarctic Ice Sheet ◽

West Antarctic Ice Sheet ◽

West Antarctic

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The origin of till sequences by subglacial sediment deformation beneath mid-latitude ice sheets

Annals of Glaciology ◽

10.1017/s026030550001524x ◽

1996 ◽

Vol 22 ◽

pp. 75-84 ◽

Cited By ~ 75

Author(s):

G. S. Boulton

Keyword(s):

North American ◽

Large Scale ◽

Ice Sheets ◽

Ice Sheet ◽

Glacial Cycle ◽

Erosion And Deposition ◽

The North ◽

Sediment Deformation ◽

Source Materials ◽

The Last Glacial

A theory of erosion and deposition as a consequence of subglacial sediment deformation over beds of unlithified sediment is reviewed and applied to large-scale till sequences formed on the southern flanks of the North American and British and European ice sheets during the last glacial cycle. The distribution of till thickness, till lithology in relation to source materials and intra-till erosion surfaces along a flowline in the Michigan lobe of the North American ice sheet are shown to be compatible with the deformational theory but not with other modes of till genesis. It is then demonstrated, in the case of the British ice sheet, how the assumption of a deformational origin for tills can be used to infer time-dependent patterns of ice-sheet dynamic behaviour. By reference to an example from the Netherlands, it is argued that many till sequences interpreted as melt-out tills are more likely to have formed by subglacial sediment deformation.

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Evolution of the large-scale atmospheric circulation in response to changing ice sheets over the last glacial cycle

Climate of the Past ◽

10.5194/cp-10-1453-2014 ◽

2014 ◽

Vol 10 (4) ◽

pp. 1453-1471 ◽

Cited By ~ 57

Author(s):

M. Löfverström ◽

R. Caballero ◽

J. Nilsson ◽

J. Kleman

Keyword(s):

Atmospheric Circulation ◽

Large Scale ◽

Ice Sheets ◽

Ice Sheet ◽

Laurentide Ice Sheet ◽

Glacial Cycle ◽

Mean Flow ◽

Geological Evidence ◽

Last Glacial ◽

The Last Glacial

Abstract. We present modelling results of the atmospheric circulation at the cold periods of marine isotope stage 5b (MIS 5b), MIS 4 and the Last Glacial Maximum (LGM), as well as the interglacial. The palaeosimulations are forced by ice-sheet reconstructions consistent with geological evidence and by appropriate insolation and greenhouse gas concentrations. The results suggest that the large-scale atmospheric winter circulation remained largely similar to the interglacial for a significant part of the glacial cycle. The proposed explanation is that the ice sheets were located in areas where their interaction with the mean flow is limited. However, the LGM Laurentide Ice Sheet induces a much larger planetary wave that leads to a zonalisation of the Atlantic jet. In summer, the ice-sheet topography dynamically induces warm temperatures in Alaska and central Asia that inhibits the expansion of the ice sheets into these regions. The warm temperatures may also serve as an explanation for westward propagation of the Eurasian Ice Sheet from MIS 4 to the LGM.

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Extent and dynamics of the West Antarctic Ice Sheet on the outer continental shelf of Pine Island Bay during the last glaciation

Marine Geology ◽

10.1016/j.margeo.2006.04.001 ◽

2006 ◽

Vol 230 (1-2) ◽

pp. 53-72 ◽

Cited By ~ 92

Author(s):

Jeffrey Evans ◽

Julian A. Dowdeswell ◽

Colm Ó Cofaigh ◽

Toby J. Benham ◽

John B. Anderson

Keyword(s):

Continental Shelf ◽

Ice Sheet ◽

Outer Continental Shelf ◽

The West ◽

Antarctic Ice Sheet ◽

West Antarctic Ice Sheet ◽

West Antarctic ◽

Last Glaciation

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The glacial geomorphology of the Antarctic ice sheet bed

Antarctic Science ◽

10.1017/s0954102014000212 ◽

2014 ◽

Vol 26 (6) ◽

pp. 724-741 ◽

Cited By ~ 25

Author(s):

Stewart S.R. Jamieson ◽

Chris R. Stokes ◽

Neil Ross ◽

David M. Rippin ◽

Robert G. Bingham ◽

...

Keyword(s):

Large Scale ◽

Landscape Evolution ◽

Ice Sheets ◽

Ice Sheet ◽

Glacial Erosion ◽

Antarctic Ice Sheet ◽

The Past ◽

Valley Network ◽

The Antarctic ◽

Antarctic Ice Sheets

AbstractIn 1976, David Sugden and Brian John developed a classification for Antarctic landscapes of glacial erosion based upon exposed and eroded coastal topography, providing insight into the past glacial dynamics of the Antarctic ice sheets. We extend this classification to cover the continental interior of Antarctica by analysing the hypsometry of the subglacial landscape using a recently released dataset of bed topography (BEDMAP2). We used the existing classification as a basis for first developing a low-resolution description of landscape evolution under the ice sheet before building a more detailed classification of patterns of glacial erosion. Our key finding is that a more widespread distribution of ancient, preserved alpine landscapes may survive beneath the Antarctic ice sheets than has been previously recognized. Furthermore, the findings suggest that landscapes of selective erosion exist further inland than might be expected, and may reflect the presence of thinner, less extensive ice in the past. Much of the selective nature of erosion may be controlled by pre-glacial topography, and especially by the large-scale tectonic structure and fluvial valley network. The hypotheses of landscape evolution presented here can be tested by future surveys of the Antarctic ice sheet bed.

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Taxonomy of Middle Miocene foraminifera from the northern Namibian continental shelf

Zootaxa ◽

10.11646/zootaxa.5091.1.1 ◽

2022 ◽

Vol 5091 (1) ◽

pp. 1-55

Author(s):

EUGENE W. BERGH ◽

JOHN S. COMPTON

Keyword(s):

Continental Shelf ◽

Middle Miocene ◽

Regional Distribution ◽

Outer Continental Shelf ◽

Benthic Species ◽

Planktic Foraminifera ◽

Benguela Upwelling ◽

Orbulina Universa ◽

Recent Sediments ◽

First Time

Middle Miocene foraminifera from the northern Namibian outer continental shelf are indicators of a period prior to the initiation of the Benguela Upwelling System (BUS). This study provides an update to the occurrence and taxonomy of Miocene foraminifera from the continental margin of Namibia. The taxonomy of 51 benthic and 12 planktic foraminiferal species from the northern Namibian shelf are discussed, their stratigraphic significance given, and their ecological preferences and regional distribution summarised within this study. The identification of extinct planktic foraminifera provided key stratigraphic control for the middle Miocene strata of this region. The taxa identified in this study provide a distinct and different assemblage to the overlying younger strata. Many of the species recorded in this study have not been identified in the region and are reported for the first time from the middle Miocene on the southwestern continental shelf of Africa, off Namibia. A total of 47 species are identified and discussed for the first time from this region. Nineteen species recorded in this study are extinct and eleven taxa reported here have previously only been reported on the genus level on the southwestern shelf of South Africa. Seven benthic species (Amphicoryna scalaris, Marginulina obesa, Glandulina laevigata, Globocassidulina subglobosa, Uvigerina peregrina, Sphaeroidina bulloides and Melonis affinis) and two planktic species (Globigerina bulloides and Orbulina universa) did not disappear from the regional stratigraphy and continued to occur in Plio-Pleistocene to Recent sediments along the southwestern continental shelf of Africa.

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Simulation of the Greenland Ice sheet over two glacial cycles: Investigating a sub-ice shelf melt parameterisation and relative sea level forcing in an ice sheet-ice shelf model

10.5194/cp-2017-132 ◽

2017 ◽

Cited By ~ 1

Author(s):

Sarah L. Bradley ◽

Thomas J. Reerink ◽

Roderik S. W. van de Wal ◽

Michiel M. Helsen

Keyword(s):

Continental Shelf ◽

Sea Level ◽

Ice Sheets ◽

Ice Sheet ◽

Greenland Ice Sheet ◽

Ice Shelf ◽

Temporal Behaviour ◽

The North ◽

Non Local ◽

Continental Shelf Break

Abstract. Observational evidence, including offshore moraines and sediment cores confirm that at the Last Glacial maximum (LGM) the Greenland ice sheet (GrIS) grew to a significantly larger spatial extent than seen at present, grounding into Baffin Bay and to the continental shelf break. Given this larger spatial extent and it is close proximity to the neighboring Laurentide (LIS) and Innuitian Ice sheet (IIS), it is likely these ice sheets will have had a strong non-local influence on the spatial and temporal behaviour of the GrIS. Most previous paleo ice sheet modelling simulations recreated an ice sheet that either did not extend out onto the continental shelf; or utilized a simplified marine ice parametersiation and therefore did not fully include ice shelf dynamics, and or the sensitivity of the GrIS to this non-local signal from the surrounding ice sheets. In this paper, we investigated the evolution of the GrIS over the two most recent glacial-interglacial cycles (240 kyr BP to present day), using the ice sheet-ice shelf model, IMAU-ICE and investigated the influence of the LIS and IIS via an offline relative sea level (RSL) forcing generated by a GIA model. This RSL forcing controlled via changes in the water depth below the developing ice shelves, the spatial and temporal pattern of sub-ice shelf melting, which was parametrised in relation to changes in water depth. In the suite of simulations, the GrIS at the glacial maximums coalesced with the IIS to the north, expanded to the continental shelf break to the south west but remained too restricted to the north east. In terms of an ice-volume equivalent sea level contribution, at the Last Interglacial (LIG) and LGM the ice sheet added 1.46 m and −2.59 m to the budget respectively. The estimated lowering of the sea level by the Greenland contribution is considerably more (1.26 m) than most previous studies indicated whereas the contribution to the LIG high stand is lower (0.7 m). The spatial and temporal behaviour of the northern margin was highly variable in all simulations, controlled by the sub surface melt (SSM), which was dictated by the RSL forcing and the glacial history of the IIS and LIS. In contrast, the southwestern part of the ice sheet was insensitive to these forcing’s, with a uniform response in an all simulations controlled by the surface air temperature (SAT) forcing, derived from ice cores.

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Supplemental Material: Early and middle Miocene ice sheet dynamics in the Ross Sea: Results from integrated core-log-seismic interpretation

10.1130/gsab.s.14356205.v3 ◽

2021 ◽

Author(s):

L F Pérez ◽

et al.

Keyword(s):

Middle Miocene ◽

Ross Sea ◽

Seismic Interpretation ◽

Seismic Processing ◽

Additional Information ◽

Reflection Seismic ◽

Spatial Velocity ◽

Drill Site ◽

Ice Sheet Dynamics ◽

Reflection Tomography

Additional information regarding methods (Reflection seismic processing, Drill-site measurements, Core-log-seismic correlations, Spatial Velocity calculations, and Reflection Tomography model) and regional stratigraphy descriptions, as well as detailed considerations regarding the opal distribution and depth.

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Exploring the impact of atmospheric forcing and basal drag on the Antarctic Ice Sheet under Last Glacial Maximum conditions

The Cryosphere ◽

10.5194/tc-15-215-2021 ◽

2021 ◽

Vol 15 (1) ◽

pp. 215-231

Author(s):

Javier Blasco ◽

Jorge Alvarez-Solas ◽

Alexander Robinson ◽

Marisa Montoya

Keyword(s):

Boundary Conditions ◽

Continental Shelf ◽

Last Glacial Maximum ◽

Ice Sheets ◽

Ice Sheet ◽

Shelf Break ◽

Ice Volume ◽

Basal Friction ◽

The Antarctic ◽

Continental Shelf Break

Abstract. Little is known about the distribution of ice in the Antarctic Ice Sheet (AIS) during the Last Glacial Maximum (LGM). Whereas marine and terrestrial geological data indicate that the grounded ice advanced to a position close to the continental-shelf break, the total ice volume is unclear. Glacial boundary conditions are potentially important sources of uncertainty, in particular basal friction and climatic boundary conditions. Basal friction exerts a strong control on the large-scale dynamics of the ice sheet and thus affects its size and is not well constrained. Glacial climatic boundary conditions determine the net accumulation and ice temperature and are also poorly known. Here we explore the effect of the uncertainty in both features on the total simulated ice storage of the AIS at the LGM. For this purpose we use a hybrid ice sheet shelf model that is forced with different basal drag choices and glacial background climatic conditions obtained from the LGM ensemble climate simulations of the third phase of the Paleoclimate Modelling Intercomparison Project (PMIP3). Overall, we find that the spread in the simulated ice volume for the tested basal drag parameterizations is about the same range as for the different general circulation model (GCM) forcings (4 to 6 m sea level equivalent). For a wide range of plausible basal friction configurations, the simulated ice dynamics vary widely but all simulations produce fully extended ice sheets towards the continental-shelf break. More dynamically active ice sheets correspond to lower ice volumes, while they remain consistent with the available constraints on ice extent. Thus, this work points to the possibility of an AIS with very active ice streams during the LGM. In addition, we find that the surface boundary temperature field plays a crucial role in determining the ice extent through its effect on viscosity. For ice sheets of a similar extent and comparable dynamics, we find that the precipitation field determines the total AIS volume. However, precipitation is highly uncertain. Climatic fields simulated by climate models show more precipitation in coastal regions than a spatially uniform anomaly, which can lead to larger ice volumes. Our results strongly support using these paleoclimatic fields to simulate and study the LGM and potentially other time periods like the last interglacial. However, their accuracy must be assessed as well, as differences between climate model forcing lead to a large spread in the simulated ice volume and extension.

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